Beam locking device



May 5 1942- H. A. HADLEY 2,281,838

BEAM LOCKING DEVICE Filed June 20, 1940 ATTORN EY Patented May 5, 1942 BEAM' lLOCKING DEVICE Harlan A.` Hadley, River Edge, N. J., assigner to Fairbanks, Morse & Co., Chicago, Ill., a corporation of Illinois Appiication June V20, 1940, Serial-No. 341,4l7

(Cl. Z55- 49) 3 Claims.

This invention relates to weighing scales and more particularly to improvements in locking means therefor.

The object of the invention is to provide an improved'electrically operated locking device for immobilizing a scale beam.

The object is attained in the provision of coactingy jaws disposed ony opposite sides of the scale for movement toward and lfrom each other in a direction transverse to the direction of beamv E movement.A The jaws are operated to clamp the beam by means of a solenoid `acting through a toggle mechanism, a spring serving to move the jaws out yof engagement with the beam when the solenoid isdeenergized. As distinguished from other types of beam locks wherein the securing elements engage the upper and lower edges of the beam and operate to move the beam and loci: it in a definite position, the device of this invention operates to immobilize the beamin the precise position thereof at the time the solenoid is energized.

The invention consists in the combination, arn rangement and construction of parts as hereinafter described and claimed.

In the accompanying drawing, Fig. i is a front elevational view of the device of the invention, the beam and solenoid appearing in dotted outline, and Fig. 2 is a side elevational view of the device shown in Fig. 1.

Referring now to the drawing by characters of reference, F designates a frame comprising a generally U-shaped bracket part, the legs 5 of which terminate in inverted U-shaped arms 6. Mounting feet I project laterally from legs 5 near the lower ends thereof, such feet having apertures 8 for the reception of mounting bolts (not shown) and by which the frame F is adapted to be secured to a suitable frame part of the scale. In the preferred arrangement of frame F .with respect to the scale beam, designated B, the frame F is mounted on the scale frame (not shown) with the legs 5 equally spaced on opposite sides of beam B and extending parallel to the plane of beam movement. The legs 5 are provided near their upper ends with openings 9 and the depending extremities i of the arms 6 are provided with openings II coaxial with openings 9 and coacting therewith to provide guideways for plunger rods I2. Thus plunger rods I2 are mounted in coaxial relation on opposite sides of the beam for reciprocating movement in a direction transverse to the plane of beam movement. The inner ends of rods I2 are provided with clamping heads I3 consisting of discs, the confronting faces of which are covered with a layer I4 of rubber or leather to provide for a frictional gripgwith the side surfaces of the beam.

Actuation of the'rods I2 is eifected by means of levers I5v which arefulcrumed approximately niidwayof their rods-cn-bearing bolts Iii-secured to ribs Il lformed integrally on legs 5 oi? the frame F, the levers I5being therebymounted for pivotal movement in a common plane transverse to the plane of beam movement. As appears in Fig. 2, each of the levers is provided with a biiurcated upper end, the furcations I8 extending to opposite sides of the associated rod I3. The furcations I8 have threaded apertures through which extend screws ES whoseinner ends project into an annular space formed between the flanges 2t of paired collars 2! which are secured on the rods I2. The ends of screws I9 are closely conlined between the confronting faces of anges 2`and engage the same to transmit movement of the lever to therod.

The levers I5 are interconnected at their lower ends by a toggle joint consisting of adjustable links, each link comprising yoke pieces 22 and 23 threaded on the ends of a threaded rod 24. The yoke pieces 22 at the outer ends of the toggle links are attached as by pivot pins 25 to the lower ends of the levers I5, and the inner yoke pieces 23 are connected together and fastened to a main plunger rod 26 by a pin 21. Main plunger 2B is mounted to slide in recesses formed in vertically spaced bosses 2B and 29, boss 28 projecting forwardly from a bridge piece 30 that transverses frame arms 5, and boss 29 projecting forwardly from the frame at its lower cross part 3! Plates 32 secured to the bosses 28 and 29 by screws 33 serve to retain the plunger rod 26 in the boss recesses. A coil spring 34 on the main plunger rod is maintained in compressed condition between a collar 35 secured to said rod, and the lower cross part 3| of the frame. The spring 34 acting upwardly on collar 35, through plunger 26, the toggle links, and levers I5, the said spring acts on plungers I2 yieldingly to hold the same out of engagement with the beam B. A collar 3S secured to plunger 26 below the frame is adapted to engage the under surface of cross part 3| to limit the extent of upward movement of plunger 26 under the action of spring 34.

Plunger 25 is adapted to be drawn downwardly (to cause the beam plungers I2 to move convergingly against the opposite sides of the beam B), by means of an electromagnet, comprising a solenoid S and a core member movable therein. The movable armature or core 3'1 of solenoid S is connected to plunger 26 by a link 38 and a yieldable coupling device. Such device comprises a yoke member having spaced, opposed legs 39 connected at their lower ends by an integral cross part 40 from which depends laterally spaced lugs 4l. Link 38 is pivotally attached to lugs 4l by a pin 42. Secured to and between the upper ends of legs 39 by bolts 43 is a block 44, said block having a vertical bore through which the plunger rod 26 extends. A coil spring 45 on plunger 2B, disposed below block 44 and confined between it and a retainer washer 46 secured to the lower end of the plunger, acts to resist downward movement of the coupling yoke relative to the plunger 26. Movement of the plunger inwardly of the coupling yoke is limited by a collar 41 secured to the plunger above block 44. Spring 45 is stronger, or relatively more rigid than spring 34 so that actuating movement of the solenoid armature will be transmitted to the plunger rod 26 and not lost in the coupling.

It will appear that when solenoid S is energized to draw the main plunger downwardly, the plungers l2 are caused to move toward each other and into clamping engagement with the sides of the beam. Displacement of the solenoid armature in excess of that required to lock the beam is taken up by the coupler spring 45, which, accordingly acts to prevent undue or excessive strain in the locking mechanism.

Having described my invention, what I claim and desire to secure by Letters Patent is:

l. in a scale having a movable beam, a locking device for said beam comprising a U-shaped frame member having arm portions extending Y vertically on opposite sides oi the beam, beamengageable rods mounted on said arms for longitudinal sliding movement transverse to the direction of beam movement, said rods being adapted to clamp the beam between the inner ends thereof, means operatively interconnecting said rods for conjoint movement toward and from each other, said means including levers connected to said rods and a toggle mechanism operatively interconnecting the levers, and an actuating plunger connected to the center pivot of the toggle mechanism.

2. A locking device for a scale beam comprising a U-shaped frame having arm portions extending vertically on opposite sides of said beam, beam-engageable rods mounted in aligned relation on said arms for endwise movement transverse to the direction of beam movement, an actuating plunger mounted on said frame for movement substantially in the plane of beam movement, means operatively connecting said rods for movement toward and from each other by said plunger, said means including an actuating lever for each rod and a toggle link connecting each lever to said plunger, and electromagnetic actuating means for said plunger.

3. The combination in a scale, a scale beam, an electrically operated device for immobilizing said beam, comprising a U-shaped frame member, having a transverse portion, and leg portions eX- tending vertically on opposite sides of the beam, clamping rods slidably mounted on said leg portions ior endwise movement transverse to the direction of beam movement, said rods being in aligned relation and adapted to engage the opposite sides of the beam and clamp the same between the inner end surfaces thereof, opposed levers on the frame, each connected at its outer end to one of the clamping rods, a toggle joint comprising toggle link members of adjustable length, interconnecting the inner ends of said levers, an actuating plunger extending vertically through said transverse frame portion, connected to the center pivot of said toggle mechanism,

electromagnetic means including a movable driving member, and a resilient coupling interconnecting said plunger and driving member.

HARLAN A. HADLEY. 

